(Adds interior ministry statement)
BAGHDAD, Feb 5 (Reuters) - Four bombs struck near Baghdad's heavily-fortified "Green Zone" and a busy square in the centre of the capital on Wednesday, killing at least 13 people, security sources said.
The blasts came a day after two rockets were fired into the Green Zone, home to the prime minister's office and Western embassies, and are likely to heighten concerns about Iraq's ability to protect strategic sites as security deteriorates.
On Wednesday, security sources said two parked car bombs were detonated opposite the Ministry of Foreign Affairs, killing five people. The Interior Ministry said in a statement the attack was carried out by a suicide bomber who blew himself up as he was being searched.
The other car was driven by a suicide bomber who blew himself and the vehicle up outside a restaurant close to a checkpoint one street away from the Green Zone, killing four people, the security sources said.
Another explosion near Khullani Square in central Baghdad left four others dead.
No group immediately claimed responsibility for the attacks, but Sunni Islamist militants have been regaining ground in Iraq, particularly in Anbar province, where they overran two cities on Jan. 1. (Reporting by Raheem Salman and Kareem Raheem; Writing by Isabel Coles; Editing by Andrew Heavens and Elizabeth Piper)